.300 whisper crimp die?

[snowhack]

I'm new to the site. Howdy. Pretty nice site.

I'm getting into .300 Whisper and reloading it. I got the Redding two die set. I'm making brass from once fired .223s. Its going through a semi-auto (AR-15) so I need to crimp the bullets in. I can't find a crimp die. I'm guessing I may be able to use a 7.62x39 crimp die, but I don't want to buy it until I know for sure. Will it work or is there a specific die for this cal.? Thanks.

[Quarterbore]

I use Redding dies and they have a built in crimping ring in the seating die. I have not previously crimped my 300/221 loads but I will need to start with my latest project...

http://www.redding-reloading.com/pag...istolsets.html

I have not seen a taper crimp made for the 300 Whisper...

[pug]

The Redding dies have a built in crimper but the cases have to be 221 fireball length (1.4") to use it and of course the bullets need a cannelure. Unless you know your chamber will take the 1.4" brass you should not trim to that length for safety. If you are using 223 brass trimmed to 1.355" then most are using the M1 carbine Lee factory crimper I think. It puts a wide crimp on but it doesn't take much and another member posted a neat trick to move the crimp up higher so it isn't as wide. You can machine off the shell holder and bottom of die to make the Redding crimper work with shorter brass but I haven't experienced any problems using the Lee factory crimper.

[snowhack]

I didn't relize the seater had a crimper,Cool. I will look into the M-1 crimper just to get a good solid crimp. I plan on using 220+ Gr slugs. Thanks.

[too_many_hobbies]

Okay, I am confused, again! I thought I read on here that you do not need to crimp. I am using the 2-die Redding set in a Dillon RL550B press, Keith_Davis brass that measures 1.355", Sierra 220 Match King bullets, in an AR-15. If I need to crimp, please tell me what to do or what to get...

[pug]

My rule of thumb is when I get close to 150 gr in bullet weight and will be using it in a semi I start thinking about crimping. The reason behind it is a 150 grain bullet has enough mass that if slammed into a chamber by the action the bullet can become unseated. This will cause pressure to drop in a subsonic round low enough that the bullet will not exit the barrel . Many variables involved such as bullet weight, length, neck tension and action speed. Your bullet may be long enough to not come out even if it wanted to. If you have a semi the easiest thing to do is measure overall length and hand cycle one from the magazine. Remeasure it and see if it is acceptable to you. Non semis are not as big a problem although there are those who crimp for everything. Personally if I am trying to put five into a .1" group I wouldn't consider crimping but then I haven't come close to that with a semi yet.